package com.jzoffer2;

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

/**
 * TODO
 *
 * @author lefly
 * @version 1.0
 * @classname No50
 * @description
 * @date 2021/3/8 下午6:49
 */
public class No50 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        char res = firstUniqChar(s);
        System.out.println(res);
    }

    public static char firstUniqChar(String s) {
        if(s == null || s.length() == 0){
            return ' ';
        }
        char[] array = s.toCharArray();
        Map<Character,Boolean> map = new HashMap<>();
        for(char c:array){
            map.put(c,!map.containsKey(c));
        }
        for(char c:array){
            if(map.get(c)){
                return c;
            }
        }
        return ' ';

    }

}
